Yes. FINALLY. Really sorry.
Having read my blathering post, I've come back to the top and am putting in a checklist of steps, so that -hopefully- between the short list and my blather, it will make sense. If it doesn't, you may pelt me with acrylic yarn. Or ask questions. Whichever seems most appropriate.
-Figure 8% of your 100% figure. For me, it is 18 stitches. (222 x 8% = 18) These are your armpit stitches.
-Knit across the body to where you're putting the first sleeve. Put armpit stitches on stitch holders, both on the body and the sleeve. (I suggest using an even number of stitches for the body, and one more for the sleeve, to make grafting easier later; mine was 18 stitches body, 19 stitches sleeve.)
-Put the two arm pits together so they meet, like they will when the sweater is finished.
-Put some kind of stitch marker on the body needle. Knit the sleeve stitches onto the body needle. Put another stitch marker. Knit across the back of sweater.
-Repeat for the other sleeve, when you knit across to it. Don't forget the stitch markers.
Confused? I hope to hell not. Details, blather, and photos of the process below.
So. The whole point of doing a sweater is, you know, having a sweater. It needs sleeves. The sleeves need to be opposite each other, on the body. Can't stress that enough. And if there's a cardigan opening, it needs to be equidistant, between the sleeves. Sure, you're laughing, going "no kidding", but there have been sweaters produced with arms in the wrong place. More than once. And I'm not the only one who has done it.
Now, if you'd marked the sides of your sweater as you knit the body, with stitch markers or loops of string, you know where the arm pits go. If not, you might wanna do that, now. Get your 100% figure, divide it in half. That gives you the number of stitches on front and back. (My 100% figure is 222, so that's 111 each, front and back.)
Remember, steek stitches (for cut cardigans) do not go in the 100% figure. And the steek? It goes in the middle of the front. Between the arms. Just sayin'.
You will put armpit stitches on holders (I suggest actual stitch holders, rather than putting them on a string, because the string allows too much stretch and distortion). Then you will put all the other stitches on a single circular needle: Front of sweater, outside of sleeve, back, outside of other sleeve, then the front again. (Giving a quick overview before digging into details.)
Why don't I shut up now and put up some pictures? There's an idea.
Sleeve with armpit stitches on stitch holders.
Body, with stitches on stitch holders.
Getting ready to knit the sleeve into the body needle.
With the sleeve and body on the body needle.
From there, I knit across the back and repeated the entire process on the other sleeve.
The advantage of doing it this way, rather than simply shoving stitches on and off needles and shuffling them around that way (which you are welcome to do instead) is, it reduces the odds of dropped stitches. It also makes it possible to knit one of these sweaters with just two circular needles, one for sleeves and one for body. Knit on the first sleeve, knit to where the second sleeve belongs, use your newly empty sleeve needle to make the second sleeve, knit it on, and you're ready to go.
With the sleeves and body put together, you need to knit an inch or two plain. This dictates the depth of the arm holes in your finished product. That is largely a matter of personal taste. I would do at least one inch, possibly two or three, depending. Things to consider:
-Smaller people need less arm room than larger people. (Kid sweater? One inch is fine. Medium adult sweater? Probably two. Really large adult sweater? Consider three.)
-Jackets and cardigans and pullovers intended to be worn over other clothes are a great deal more comfortable with larger arm holes.
For reference, and if anyone's curious, I'm doing probably two and a half inches on mine. It's a cardigan and I like my clothes on the loose side, usually.
After this will be shoulder decreasing and possible neck decreasing. Now's the time to decide if you want a crew neck or a V-neck.